У вашего броузера проблема в совместимости с HTML5
In this tutorial you are going to learn about the benefits of using subclasses and how to create your own subclasses in Xcode.
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### SWIFT TUTORIAL CONFERENCE ###
http://www.swift-tutorial-conference.net
Web: http://www.brianadvent.com
*** TUTORIAL FILES ***
http://tinyurl.com/zjqeu2m
https://github.com/brianadvent/PowerOfSubclassing
***COMMENTS***
If you have questions about the video or Cocoa programming, please comment below.